Investigators are working to find out why a driver sped through a parking lot in Dunedin, striking two people and another vehicle, which then crashed into a business, the Pinellas County Sheriff's Office said.

The crash happened at the Causeway Plaza at 2672 Bayshore Blvd., which is home to Bingo Time of Dunedin and Family Fitness Centers, among other businesses. Investigators said Robert Reed, 73, was driving through the parking lot at about 3:15 p.m. when he suddenly accelerated for an unknown reason.

Reed's Audi hit a concrete wall in front of the fitness center; parts of the wall hit Jeanette Kelly, 63, who was walking into the gym. The car then hit 55-year-old bicyclist Mark Imperato before hitting a Nissan Armada driven by Robert Hupp, 65.

Reed was taken to the hospital with what were described as life-threatening injuries. Imperato and Kelly were hospitalized and were in stabled condition. Rupp was not injured.

Investigators said neither drugs nor alcohol appeared to play a factor in the crash.